This is an evil question. I've been my groups defacto DM for a long time now so actually getting to play as a player is something that hasn't happened in almost twenty years.
That said, I'm coming up with character ideas all the time, almost like a way to keep my mind preoccupied when I've got nothing else, so the answer to the question changes with the wind. I like to let the ideas come up organically, which is really just a stupid way of saying that I try not to concern myself too much with the initial inspiration being mechanical or narrative. Sometimes I get really interested in some bit of crunch and how it functions or meshes with something from another class and then weave the characters personality around that. Just as often though I'll have an idea that starts out with a personality trait, a background or even just a cool name and figure out the class down the line when it comes time to cross that bridge. It's fun for me, even if I never get to play these characters and I've got a folder on my computer loaded with pdf character sheets from concepts I've had over time.
Still, none of that answers the question so I'll have to pick. Currently my obsession is with creating a sorcerer, specifically a favored soul. I've always enjoyed playing support classes, specifically I play a lot of clerics back when I played anything. 5E has plenty to pick from in this department, I especially like Lore Bards, but the sorcerer has always been an interesting, if a bit niche, pick for this sort of role thanks to twin spell metamagic.
Twinning buff spells doesn't seem like a big deal, not to most people I think, but I think it's awesome. When you hit level five and every other caster is drooling over their fireballs, lightning bolts and spirit guardians I feel like nothing would put a bigger grin on my face than twinning a haste spell and letting the party's real damage dealers do even more. Now add to that the extra little bit of utility added to the favored soul by giving me access to the entire clerics spell list, and I'm good to go. I've even toyed with the idea of this fella multiclassing into the newer celestial warlock pact because it's thematic and opens up a couple of new avenues mechanically too.
So anyway, longer post than I was planning on. Right here, right now, that's the character I'd make if I were going to roll one up today. Tomorrow? That's a different kettle of fish.
